Large drum microscope by Trécourt and Georges Oberhaeuser, circa 1838. Signed on the drum base "Brevet d'Invention, Trécourt & Georges Oberhaeuser, Place Dauphine № 19 à Paris". Trécourt and Oberhaeuser took out a patent for this 'microscope à tourbillon' in 1837.

Horizontal microscope by Vincent & Charles Chevalier, in contemporary literature referred to as 'microscope d'Amici' (Amici type microscope), end of the year 1830. Signed on the tube "Vincent & C. Chevalier Ing[énieu]rs Opt[icie]ns, Quai de l'horloge № 69 à Paris" and on the tube cradle "CH. CHEVALIER, 154".

Pocket microscope by Charles Chevalier, referred to by the manufacturer as 'microscope diamant', 1834-1849. Signed on the tube "Charles Chevalier, Palais Royal 163, Paris".

Microscope designed by Filippo Pacini and manufactured by Giovanni Battista Amici for George John Warren Vernon, November 1845. When visiting Amici's workshop in Florence, Lord Vernon noticed Pacini's microscope being constructed (at present in the Museo Galileo, Florence) and asked Amici to make a second example.

The innovation of this model lies in the mechanical coupling of objective and stage, which eliminates the necessity for optical centering.

Circa 1877 petrological microscope by Nachet. Signed on the base: "NACHET ET FILS, 17, rue S[ain]t Séverin, Paris". The analyser was placed at the lower end of the internal tube and difficult to remove. Just above the objective, one finds an intriguing revolver holding different Bertrand lenses, allowing the use of convergent light.

Circa 1879 petrological microscope by Nachet. Signed on the base: "NACHET ET FILS, 17, rue S[ain]t Séverin, Paris". This model represents a slightly improved design allowing the analyser to be freely removed from the tube. An absolutely identical instrument was used by the famous mineralogist Evgraf Stepanovich Fedorov and is depicted in his 1893 work 'Теодолитный метод в минералогии и петрографии' (Theodolite method in mineralogy and petrology).

A microscope for the gentleman

Early example of Nachet's 'large model' microscope, 1853-4. The working instrument of Frederick William Pavy. Signed on the arm: "NACHET, Opticien, à Paris, rue Serpente, 16" and on the case: "Dr F. W. Pavy". In 1853, like many British medical men, Pavy went to study medicine in Paris and returned to London the following year. This microscope dates from exactly that period. It therefore appears that Pavy took a microscope with him on his return, just like many foreign medical students at the time. Until the introduction of the 'large perfected model' circa 1860, this stand was the top of the range.

Prototype of Nachet's 'large perfected model', most likely made for Frédéric Villot, 1857-60. Signed on the base: "NACHET ET FILS, Rue Serpente, 16, Paris". This prototype of the 'grand modèle perfectionné' includes quite a number of novelties, of which many did not survive in the production version. The coarse focusing is not by the usual rack and pinion, but by a chain winding round a spindle controlled by the wheels. The chain mechanism is contained within a square vertical limb. The knurled wheel on top of the body-tube arm is not a fine focus knob as one might expect, but instead allows the body of the microscope to be detached. Fine focus is by a small lever located in the middle of the tube. The fine focusing mechanism consists of a double interior tube, on which the objective lenses are mounted in such a way that they revert when accidentally touching the object on the stage. In addition, this prototype comes with a substage condenser for oblique illumination (of diatoms) made on request by Villot. Another intriguing feature is a fusee chain blocking the inclination of the instrument.

Circa 1850, microscope makers in Paris did not offer a microscope suited for the wealthy amateur microscopist, who was typically engaged in a competition to resolve test objects such as diatoms. Gentleman microscopists had to turn to the London makers (Powell and Ross) for an impressive microscope stand, fitted with the most powerful objective lenses available. These objective lenses tended to be characterized by an unusably large aperture and short focal length, resulting in a very short working distance, making them inappropriate to any other fields of study and requiring the use of curious illumination systems.

In the late 1850s, starting from his 'large model', Nachet finally did conceive a microscope for the gentleman microscopist: the 'perfected grand model'. The prototype of this new top of the range 'grand modèle perfectionné' appears to have been made at the request of a special client: Frédéric Villot.

Villot was a wealthy gentleman in relation with all the microscope makers of Paris and was not only collecting diatom mounts - as could be expected - but also antique books on microscopy. In 1861, the controversial restorations of paintings by Rubens and Raphael forced Villot to resign as paintings curator of the Louvre Museum. A purely administrative role of 'secretary general of the museum' was created especially for Villot and meant that he could spend even more time on his pastime: microscopy.

Early example of Nachet's 'large perfected model', 1860-2. Signed on the base: "NACHET ET FILS, Rue Serpente, 16, Paris". Contrary to the prototype, in this production version the square vertical limb contains a rack and not a fusee chain. In addition, the body-tube arm and the tube can no longer be detached.